1. Field of Invention
This invention pertains to the art of methods and apparatuses for yard vacuum units, and more specifically to methods and apparatuses for an efficient impeller assembly used in a yard vacuum unit.
2. Description of the Related Art
Yard vacuum units are used to create a vacuum whereby yard debris, such as sticks, leaves, grass clippings and other such foliage, can be collected. Typically, the vacuum unit draws the debris into a nozzle and then deposits the debris into a debris collecting bag where the debris can then be disposed of. It is well known in the field of such vacuum units to provide impeller assemblies that are used to create the vacuum power. Known impeller assemblies are generally well suited for their intended purpose. However, known impeller assembly efficiencies are relatively low.
Applicants have discovered an impeller assembly that provides substantially greater vacuum efficiency than is currently known in the art. The difficulties inherit in the art are therefore overcome in a way that is simple and efficient, while providing better and more advantageous results.
According to one aspect of the present invention, a yard vacuum unit includes a deck including upper and lower housing members that form a discharge outlet, a plurality of ground engaging wheels operatively connected to the deck, and a nozzle operatively connected to the deck. An engine is mounted to the deck and includes a drive shaft. An impeller assembly is used to draw yard debris in through the nozzle and out through the discharge outlet and is positioned between the upper and lower housing members. The impeller assembly includes an impeller plate having an outer periphery and first and second surfaces, a hub fixedly connected to the impeller plate, and a plurality of fan blades each having first and second ends and first and second sides. The hub includes a hole that that operatively receives the drive shaft. Each fan blade first end is fixedly connected to the hub all along the first end and each fan blade first side is fixedly connected to the impeller plate all along the first side. In this way, a continuous airtight seal is formed along the entire first end of each fan blade with the hub and along the entire first side with the impeller plate. Each second end extends to the outer periphery of the impeller plate.
According to another aspect of this invention, each of the first sides of the fan blades and the impeller plate form first and second intersection surfaces each having a radius R1 that is at least 0.25 inches. Similarly, each of the first ends of adjacent fan blades and the hub form a connection surface having a radius R2 that is at least 0.50 inches.
According to still another aspect of this invention, the impeller plate, said hub and said plurality of fan blades are formed in a one piece cast. Preferably this cast is formed of Aluminum.
One advantage of this invention is that vacuum unit efficiency is increased about 30% over known impeller assemblies.
Another advantage of this invention is that it is easy and inexpensive to manufacture and use.
Still other benefits and advantages of the invention will become apparent to those skilled in the art to which it pertains upon a reading and understanding of the following detailed specification.